Hot and cold forming hammer and method of assembly

ABSTRACT

Methods for manufacturing improved free-swinging hammermill hammer configurations are disclosed and described and include steps commonly associated with one or more processes selected from the group of hot working, cold working, and MIG welding. The free-swinging hammermill hammer configurations are for comminution of materials such as grain and refuse. The hammer configurations of the present disclosure are adaptable to most hammer mill or grinders having free-swinging systems. The improved configurations improve installing, removing, and cleaning hammer components within the hammermill. Additionally, the hammer configurations of the present disclosure improve the overall efficiency of the hammermill during operation.

CROSS REFERENCE TO RELATED APPLICATIONS

This is a continuation-in-part application which claims priority under35 U.S.C. § 120 to U.S. Ser. No. 15/912,056, filed Mar. 5, 2018. Theparent application, U.S. Ser. No. 15/912,056, claimed priority under 35U.S.C. § 119 to provisional patent applications U.S. Ser. No.62/595,291, filed Dec. 6, 2017, U.S. Ser. No. 62/579,469, filed Oct. 31,2017, and U.S. Ser. No. 62/548,180, filed Aug. 21, 2017. All of theseapplications are herein incorporated by reference in their entirety,including without limitation, the specification, claims, and abstract,as well as any figures, tables, appendices, or drawings thereof.

FIELD OF THE INVENTION

The invention relates generally to non-forged rotary hammermill hammers.

BACKGROUND OF THE INVENTION

U.S. Pat. Nos. 7,140,569 and 7,621,477, which are both incorporated byreference in their entirety herein and are both to Young, note severalindustries rely on impact grinders or hammermills to reduce materials toa smaller size. For example, hammermills are often used to processforestry, agricultural products, and minerals and to recycle materials.Materials processed by hammermills include grains, animal food, petfood, food ingredients, mulch, and bark.

Whole grain corn must be cracked before further processing and may becracked after tempering yet before conditioning. Particle size reductionmay be accomplished with a hammermill including successive rows ofrotating hammer like devices spinning on a common rotor next to oneanother comminute the grain product. Several methods for size reductionas applied to grain and animal products are described in Watson, S. A. &P. E. Ramstad, ed. (1987, Corn: Chemistry and Technology, Chapter 11,American Association of Cereal Chemist, Inc., St. Paul, Minn.), thedisclosure of which is hereby incorporated by reference in its entirety.

Hammermills may also be generally referred to as crushers and typicallyinclude a steel housing or chamber containing a plurality of hammersmounted on a rotor and a suitable drive train for rotating the rotor. Asthe rotor turns, the correspondingly rotating hammers come intoengagement with the material to be comminuted or reduced in size.Hammermills typically use screens formed into and circumscribing aportion of the interior surface of the housing. The size of theparticulate material is controlled by the size of the screen aperturesagainst which the rotating hammers force the material. Exemplaryembodiments of hammermills are disclosed in U.S. Pat. Nos. 5,904,306;5,842,653; 5,377,919; and 3,627,212, which are all incorporated herein.

Swinging hammers with blunt edges are typically better suited forprocessing “dirty” products, or products containing metal or stonecontamination. The rotatable hammers of a hammermill may recoilbackwardly if the hammer cannot break or push the material on impact.Even though a hammermill is designed to better handle the entry of a“dirty” products, there still exists a possibility for catastrophicfailure of a hammer causing severe damage to the hammermill andrequiring immediate maintenance and repairs.

Treatment methods such as adding weld material to the end of the hammerblade improve the comminution properties of the hammer. These methodstypically infuse the hammer edge, through welding, with a metallicmaterial resistant to abrasion or wear such as tungsten carbide. See forexample U.S. Pat. No. 6,419,173, incorporated herein by reference,describing methods of attaining hardened hammer tips or edges as arewell known in the prior art by those practiced in the arts.

Hammers are typically singular units and are not rigidly securedtogether. For example, as is shown in FIGS. 1-4 of U.S. Pat. No.7,140,569, the hammers may be slid onto a drive shaft and spacers areplaced in between each hammer. This configuration presents manypotential gaps, all of which are exposed to debris, thereby creatingexcessive or premature wear. It is therefore desirable to minimize thenumber of parts and the corresponding number of gaps to extend the lifeof the hammer assembly.

The use of separate hammers and spacers also presents removal andinstallation difficulties. While some parts may be keyed to the driveshaft, flying debris can dent or damage parts thereby making removal orinstallation difficult. The increased number of parts also complicatesthe assembly/disassembly process. Thus, there is a need in the art tosimplify the installation and replacement process and to minimize thenumber of parts being replaced.

The four metrics of strength, capacity, run time, and the amount offorce delivered are typically considered by users of hammermill hammersto evaluate any hammer to be installed in a hammermill. A hammer to beinstalled is first evaluated on its strength. Typically, hammermillmachines employing hammers of this type are operated twenty-four hours aday, seven days a week. This punishing environment requires strong andresilient material that will not prematurely or unexpectedlydeteriorate. Next, the hammer is evaluated for capacity, or morespecifically, how the weight of the hammer affects the capacity of thehammermill. The heavier the hammer, the fewer hammers that may be usedin the hammermill by the available horsepower. A lighter hammerincreases the number of hammers that may be mounted within thehammermill for the same available horsepower. More force delivered bythe hammer to the material to be comminuted against the screen increaseseffective comminution (e.g. cracking or breaking down of the material)and efficiency of the comminution process. The force delivered isevaluated with respect to the weight of the hammer. Finally, the longerthe hammer lasts, the longer the machine is able to run, resulting inlarger profits presented by continuous processing of the material in thehammermill through reduced maintenance costs and lower necessary capitalinputs. The four metrics are interrelated and typically tradeoffs arenecessary to improve performance. For example, to increase the amount offorce delivered, the weight of the hammer could be increased. However,because the weight of the hammer increased, the capacity of the unittypically will be decreased because of horsepower limitations. There isa need in the art to improve upon the design of hammermill hammersavailable in the prior art for optimization of the four (4) metricslisted above.

BRIEF SUMMARY OF THE INVENTION

Therefore, it is an object, feature, or advantage of the presentinvention to utilize a saddle or a hammer mouth which accommodates ahammer body or multiple hammer bodies.

Another object, feature, or advantage of the present invention is toimprove the securement end of free-swinging hammers for use in hammermills.

Another object, feature, or advantage of the present invention is toprovide a hammer that is easily installed and removed.

Another object, feature, or advantage of the present invention is toimprove the durability and operational runtime of hammermill hammers.

Another object, feature, or advantage of the present invention is toprovide hammers having hardened edges by such means as welding or heattreating.

Another object, feature, or advantage of the present invention is toprovide a hammer allowing for improved projection of momentum to thehammer blade tip to thereby increase the delivery of force tocomminution materials.

Another object, feature, or advantage of the present invention is toprovide a cost-effective hammer.

Another object, feature, or advantage of the present invention is toprovide an aesthetically pleasing hammer.

Another object, feature, or advantage of the present invention is toprovide hammers that improve the safety of the operator of a hammermill.

These or other objects, features, and advantages of the invention willbe apparent to those skilled in the art. The invention is not to belimited to or by these objects, features and advantages. No singleembodiment need provide each and every object, feature, or advantage.

According to some aspects of the present disclosure, an improved,non-forged hammer for use in a rotatable hammermill assembly is providedand comprises a hammer body. The hammer body includes a hammer bodyfront surface, a first end for securement within a saddle or a hammermouth, a first rod hole, and a second end for contact and delivery ofmomentum to material to be comminuted, wherein said second end has aweld hardened edge. A saddle secured to the hammer body may be securedto the hammer body. The saddle may include a bottom surface, a saddlefront surface, a first fender extending upwardly from the bottom surfaceto a first top fender edge, the first top fender edge being parallel tothe bottom surface, a second fender extending upwardly from the bottomsurface to a second top fender edge, the second top fender edge beingparallel to the bottom surface, and a second rod hole aligned with thefirst rod hole such that a hammermill rod can pass through the first andsecond rod holes.

According to other aspects of the invention, the non-forged hammerincludes a weld hardened edge welded to the periphery of the second end.The weld hardened edge has two side contact edges opposite one anotherthat partially cover the first and second hammer body edges, a topcontact edge, and tungsten carbide for increased hardness.

According to other aspects of the disclosure, the hammer body is anon-planar hammer body and comprises a recessed surface and a protrudingsurface located opposite the recessed surface. The non-forged hammer mayinclude two side contact edges opposite one another that partially coverthe first and second hammer body edges, recessed edges between therecessed surface and the hammer body front surface and at least oneother hammer body front surface, and protruding edges between theprotruding surface and at least two rear surfaces, wherein the recessededges are located below the side contact edges and the protruding edgesare located above the first rod hole.

According to other aspects of the disclosure, an improved, non-forgedhammer assembly for use in a rotatable hammermill assembly includes aplurality of non-planar hammer bodies. The non-planar hammer bodiescomprise a recessed surface located between at least two front surfaces,a protruding surface located opposite the recessed surface and betweenat least two rear surfaces, a first end for securement within a hammermouth, a first rod hole, a second end for contact and delivery ofmomentum to material to be comminuted, wherein said second end has afirst weld hardened edge, and first and second hammer body edges thatrun from the first end to the second end. The non-forged hammer assemblyalso includes the hammer mouth. The hammer mouth has a hammer mouthfront plate and a hammer mouth rear plate opposite the hammer mouthfront plate, a base, a plurality of teeth, said teeth having crown edgesrunning parallel to said base, a root edge centered between said crownedges, said non-forged hammer assembly configured to attach to ahammermill rod of the rotatable hammermill assembly. The hammer assemblymay include a plurality of planar hammer bodies, each planar hammer bodyof the plurality of planar hammer bodies comprising a planar hammer bodyfirst surface, a planar hammer body second surface opposite the planarhammer body first surface, a proximate end for securement within thehammer mouth, a first rod hole, and a distal end for contact anddelivery of momentum to material to be comminuted, wherein said distalend has a second weld hardened edge.

According to other aspects of the disclosure, a MIG welding process forembedding carbide onto a hammermill hammer includes providing a weldinggun including a control switch, a contact tip, and a gas hose, providinga wire feed unit, a welding power supply, a welding electrode wire, anda shielding gas supply, setting a flow rate of shielding gas flow to besupplied by the shielding gas supply, striking an arc by pressing thecontrol switch of the welding gun to initiate the wire feed unit, thewelding power supply, and the shielding gas flow, and hardfacing thecarbide onto the hammermill hammer. The process may be automated and mayinclude repeating the striking and hardfacing steps in order to embedcarbide onto several hammermill hammers.

Other aspects of the invention will be apparent to those skilled in theart from the following detailed description of the illustratedembodiments, accompanied by the attached drawings wherein identicalreference numerals will be used for like parts in the various views.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 provides a perspective view of an improved hammer.

FIG. 2 provides an edge view of the hammer of FIG. 1.

FIG. 3 provides a side view of the hammer of FIG. 1.

FIG. 4 provides a top view of the hammer of FIG. 1.

FIG. 5 provides a perspective view of a hammer assembly that implementsseveral hammers of FIG. 1.

FIG. 6 provides a side view of the improved hammer assembly of FIG. 5.

FIG. 7 provides a top view of the improved hammer assembly of FIG. 5.

FIG. 8 provides a prospective view of an alternative embodiment of thehammer of FIG. 1.

FIG. 9 provides a front view of the hammer of FIG. 8.

FIG. 10 provides a side view of the hammer of FIG. 8.

FIG. 11 provides a top view of the hammer of FIG. 8.

FIG. 12 provides a prospective view of another alternative embodiment ofthe hammer of FIG. 1.

FIG. 13 provides a front view of the hammer of FIG. 12.

FIG. 14 provides a prospective view of another alternative embodiment ofthe hammer of FIG. 1.

FIG. 15 provides a front view of the hammer of FIG. 14.

FIG. 16 provides a prospective view of another alternative embodiment ofthe hammer of FIG. 1.

FIG. 17 provides a front view of the hammer of FIG. 16.

FIG. 18 provides an exploded prospective view of another alternativeembodiment of the hammer of FIG. 1.

FIG. 19 provides an assembled prospective view of the hammer of FIG. 18.

FIG. 20 provides a perspective view of an improved hammer with arecessed surface.

FIG. 21 provides an edge view of the hammer of FIG. 20.

FIG. 22 provides a side view of the hammer of FIG. 20.

FIG. 23 provides a top view of the hammer of FIG. 20.

FIG. 24 provides a perspective view of a trident shaped hammerconfiguration.

FIG. 25 provides a perspective view of a pitchfork shaped hammerconfiguration.

FIG. 26 provides a perspective view of a hammer assembly that implementsseveral hammers of FIG. 1 and FIG. 20.

FIG. 27 provides a side view of the improved hammer assembly of FIG. 26.

FIG. 28 provides a top view of the improved hammer assembly of FIG. 26.

FIG. 29 provides a perspective view of a non-planar hammer assembly thatimplements several hammers of FIG. 1 and FIG. 20.

FIG. 30 provides a side view of the improved hammer assembly of FIG. 29.

FIG. 31 provides a top view of the improved hammer assembly of FIG. 29.

FIG. 32 provides a perspective view of a hammer assembly that implementsseveral hammers of FIG. 20.

FIG. 33 provides a side view of the improved hammer assembly of FIG. 32.

FIG. 34 provides a top view of the improved hammer assembly of FIG. 32.

FIG. 35 provides a perspective view of a non-planar hammer assembly thatimplements several hammers of FIG. 20.

FIG. 36 provides a side view of the improved hammer assembly of FIG. 20.

FIG. 37 provides a top view of the improved hammer assembly of FIG. 20.

FIG. 38 provides a top perspective view of an alternative improvedhammer that includes a U-shaped proximate end which may have been formedas a result of a hot-working process.

FIG. 39 provides a bottom perspective view of the alternative improvedhammer of FIG. 38.

FIG. 40 provides a side elevation view of the alternative improvedhammer of FIG. 38.

FIG. 41 provides a front elevation view of the alternative improvedhammer of FIG. 38.

FIG. 42 provides a top elevation view of the alternative improved hammerof FIG. 38.

FIG. 43 provides a bottom elevation view of the alternative improvedhammer of FIG. 38.

FIG. 44 provides a top perspective view of an additional alternativeimproved hammer that includes a U-shaped proximate end which may havebeen formed as a result of a hot-working process.

FIG. 45 provides a bottom perspective view of the alternative improvedhammer of FIG. 44.

FIG. 46 provides a side elevation view of the alternative improvedhammer of FIG. 44.

FIG. 47 provides a front elevation view of the alternative improvedhammer of FIG. 44.

FIG. 48 provides a top elevation view of the alternative improved hammerof FIG. 44.

FIG. 49 provides a bottom elevation view of the alternative improvedhammer of FIG. 44.

DETAILED DESCRIPTION

The following definitions and introductory matters are provided tofacilitate an understanding of the present invention.

The singular terms “a,” “an,” and “the” include plural referents unlesscontext clearly indicates otherwise. Similarly, the word “or” isintended to include “and” unless the context clearly indicate otherwise.The word “or” means any one member of a particular list and alsoincludes any combination of members of that list.

Reference is made to the accompanying drawings which form a part hereof,and in which is shown by way of illustration specific embodiments inwhich the invention may be practiced. These embodiments of the inventionwill be described in detail with reference to the drawings, wherein likereference numerals represent like parts throughout the several views.These embodiments are described in sufficient detail to enable thoseskilled in the art to practice the invention, and it is to be understoodthat other embodiments may be utilized and that mechanical, procedural,and other changes may be made without departing from the spirit andscope of the invention. The following detailed description is,therefore, not to be taken in a limiting sense, and the scope of theinvention is defined only by the appended claims, along with the fullscope of equivalents to which such claims are entitled.

As used herein, the terminology such as vertical, horizontal, top,bottom, front, rear, end, sides, and the like, are referenced accordingto the views presented. It should be understood, however, that the termsare used only for purposes of description, and are not intended to beused as limitations. Accordingly, orientation of an object or acombination of objects may change without departing from the scope ofthe invention.

The improved hammers 10, 11 shown in FIGS. 1-37 increase the surfacearea available to support the hammer 10, 11 relative to the thickness ofthe hammer body 12, 13. Increasing the surface area available to supportthe hammer body 12, 13 while improving securement also increases theamount of material available to absorb or distribute operationalstresses while still allowing the benefits of the free-swinging hammerdesign, e.g., recoil to non-destructible foreign objects. Theconfiguration also greatly reduces lateral movement of the hammer 10, 11and can be made wide enough to eliminate it completely. The hammer body12, 13 or the hammer saddle/mouth 30, 52 can be made wider to reducelateral movement.

The hammer body 12, 13 and the hammer saddle/mouth 30, 52 allow thetwo-piece hammer 10, 11 to be heat treated so that the hammer body 12,13 is as hard as needed to reduce hole wear and acts more like springsteel (e.g., taking some impact without breaking). If hammer body 12, 13is heat treated, the timing of the heat treatment with respect to whenhammer body 12, 13 is integrated into hammer 10, 11. This configurationallows for a denser hammer pattern and hammers thinner than theindustrial standard of ¼″ thick. However, in some situations, the hammerbody 12, 13 may not need to be heat treated to achieve the desired levelof hardness.

The width of the mounting portion of hammer 10, 11 has been increased byhammer saddle 30, thus allowing for a thinner hammer body 12, 13.Increasing the surface area available to support the hammer 10, 11improves securement and increases the amount of material available toabsorb or distribute operational stresses while still allowing thebenefits of the free-swinging hammer design, e.g., recoil tonon-destructible foreign objects. Additionally, the amount of materialsurface supporting attachment of hammer 10, 11 to a hammermill rod (notshown) is dramatically increased. This has the added benefit ofeliminating or reducing the wear or grooving of the hammermill rod (notshown).

Further benefits of the improved hammer 10, 11 include the prevention ofhammer 10, 11 “figure eighting” during hammermill operation.

FIGS. 1-4 show improved, non-forged planar hammers 10 to be installed ina hammermill assembly (not shown). Planar hammer 10 includes planarhammer body 12.

Hammer body distal end 16 has contact edges 28A-C that comminute andgrind grains, animal food, pet food, food ingredients, mulch, bark, etc.during operation of the hammermill assembly. In the embodiment shown,hammer body 12 is symmetrical across hammer body front surface 24 andhammer body rear surface 25 such that either of the side contact edges28A, 28C may be the leading edge during operation of the hammermillassembly. The side contact edge 28A/28C serving as the leading edge willwear much faster than the trailing side contact edge 28A/28C. Changingwhich side contact edge is the leading edge may be accomplished byreversing the direction of rotation of the hammermill assembly or may beaccomplished by re-installing the planar hammer 10 in the mirroredorientation. The width of the contacting edges 28A-C is substantiallyequivalent to the width of distal end 16 of the hammer body 12. It maybe preferred that contact edges 28A-C have been welded onto distal end16 using tungsten carbide to increase hardness and durability of theplanar hammer 10. It may also be preferred that side contact edges 28A,28C be stepped, as is shown in FIGS. 20-37. Other types of weldingmaterials known to those skilled in the art may also be applied.

Referring back to FIGS. 1-4, hammer body proximate end 18 is used tosecure planar hammer 10 within hammer saddle 30 and is the end whereplanar hammer body 12 attaches to the hammermill rod of a hammermillassembly (not shown). Planar hammer body 12 and hammer saddle 30 arewelded together where hammer body first side edge 20 meets saddle firstside u-shaped edge 32. Planar hammer body 12 and hammer saddle 30 arealso welded together where hammer body second side 21 meets saddlesecond side u-shaped edge 33 (not shown) meet. Welds 22 may span theentire width of side u-shaped edges 32, 33 or may be less than thetotal. Welds 22 are preferably fusion type welds, but the presentdisclosure also contemplates utilizing solid-state welding methods orother types of welding methods known to those skilled in the art. Thepresent disclosure is also not limited to the use of welds to secure theplanar hammers 10 to the hammer saddle 30. For example, the planarhammers 10 could be secured to the hammer saddle 30 via rivets or anyother known means for fastening non-forged steel together.

Saddle 30 is generally formed by first side u-shaped edge 32 and secondside u-shaped edge 33 (not shown) opposite first u-shaped edge 32. Firstand second side u-shaped edges 32, 33 are adjoined via saddle frontsurface 34 and saddle rear surface 35 (not shown) located oppositesaddle front surface 34. First side u-shaped edge 32 includes firstsaddle leg or fender 40 and second saddle leg or fender 44 which extendupward from saddle bottom surface or saddle skirt 38. The area betweensaddle fenders 40, 44 may be generally the same width as hammer body 12and fenders 40, 44 may be generally the same width as hammer body 12.First fender 40 extends upward from saddle skirt 38 until first fender40 reaches first fender top edges 42, 43. Second fender 44 extendsupward from saddle skirt 38 until second fender 44 reaches second fendertop edges 46A, 46B. Top fender edges 42, 43, 46, 47 are generallyparallel to saddle skirt 38 and are interrupted by elliptical rod holeedges 36, 37. In the embodiment shown in FIGS. 1-4, elliptical rod holeedges 36, 37 are semi-circular in nature.

In another embodiment of the invention, planar hammer body 12 does notincorporate first u-shaped edge 32. Instead, first fender 40 and secondfender 44 stop at the proximate end 18 of planar hammer body 12, similarto the configuration shown in FIGS. 8-11, 14-17, 20-23, 29-31, and34-37. In this configuration, saddle front surface 34 and saddle rearsurface 35 are substituted for front plate 34 and rear plate 35.

Planar hammer body 12 has hammermill rod hole 14 and hammermill rod holeedge 15 near proximate end 18. In the embodiment shown, hammermill rodhole edge 15 and elliptical rod hole edges 36, 37 create a continuoussurface for hammermill rod engagement. Planar hammer body 12 and saddle30 may be welded together before attachment to a hammermill rod when thehammermill (not shown) is dis-assembled. The present disclosure is alsonot limited to the use of welds to secure the non-planar hammers 11 tothe hammer saddle 30. For example, the non-planar hammers 10 could besecured to the hammer saddle 30 via rivets or any other known means forfastening non-forged steel together.

FIGS. 5-7 show an improved, non-forged hammer assembly 50 to beinstalled in a hammermill assembly using planar hammers 10 from theembodiment shown in FIGS. 1-4. As shown in FIGS. 5-7, the proximate ends18 of the planar hammer bodies 12 are now used to secure planar hammer10 within hammer mouth 52. Hammer mouth 52 is similar to hammer saddle30 but is capable of securing more than one planar hammer 10.

Planar hammer bodies 12 are welded to hammer mouth 52 where hammer bodyfirst side edges 20 meet hammer mouth first and second teeth shapedsurfaces 54, 55 (second teeth shaped surface 55 is located oppositefirst teeth shaped surface 54 and is not shown) via welds 22. Welds 22are preferably fusion type welds, but the present disclosure alsocontemplates utilizing solid-state welding methods or other types ofwelding methods known to those skilled in the art. Hammer body 12 andhammer mouth 52 may be welded together before attachment to a hammermillrod when the hammermill (not shown) is dis-assembled.

Hammer mouth 52 is generally formed by first teeth shaped surface 54having a plurality of fenders or teeth and second teeth shaped surface55 (not shown) mirroring first teeth shaped surface 54. The teeth shapedsurfaces are adjoined via puzzle piece shaped surfaces 56, 57 (rearpuzzle piece shaped surface 57 is located opposite front puzzle pieceshaped surface 56 and is not shown). In the embodiment shown, teethshaped surface 54 has six first teeth, 76A-F, which extend away frombottom surface or base 70. Similarly, second teeth shaped surface 55 hassix second teeth 78A-F positioned opposite first teeth 76A-F. Firstteeth 76A-F have first crown edges 72A-F and second teeth 78A-F havesecond crown edges 74A-F. First and second crown edges 72A-F, 74A-F areinterrupted by root edges 58A-F. Crown edges 72A-F, 74A-F are generallyparallel to bottom surface or base 70.

FIGS. 5-7 show five hammer bodies 12 interfacing with root edges 58A-Fto create a continuous surface for hammermill rod engagement, howeverany number of hammer bodies and teeth are contemplated for use in hammerassembly 50. Teeth 76A-F, 78A-F are generally the same width as hammerbody 12, but may be different widths.

FIGS. 8-19 show alternative embodiments of improved hammer 10.

The hammers shown in FIGS. 8-19 substitutes saddle 30 for variablesaddle 60; hammermill rod hole 14 for variable hammermill rod hole 62;saddle front and rear surfaces 34, 35 for variable saddle front and rearsurfaces 64, 65; and first and second first fender top edges 42, 43, 46,47 for first and second fender top edges 41, 45 (with the exception ofFIGS. 18-19).

FIGS. 8-11 do not show u-shaped edges 32, 33 and instead show planarhammer body 12 extending through the entire length of variable hammersaddle 60 (similar configurations are shown in FIGS. 14-17, 20-23,29-31, and 34-37). Variable hammer saddle 60 in FIGS. 8-11 is shown as arectangular plate secured to hammer body 12 via welds 22. Variablehammermill rod hole 62 is bored through variable hammer saddle 60 and iscircular in nature in FIGS. 8-11. Because variable hammer saddle 60 isno longer open on one-side (e.g. variable hammer saddle 60 is notu-shaped or puzzle-piece shaped) it is preferred that variable hammersaddle 60 be two separate plates, one for each side of planar hammerbody 12, so that an operator of the hammermill can still easily replaceworn or broken hammers without having to disassemble the hammermill rodfrom the hammermill assembly. However, because there are at least threeseparate pieces 12, 60, 60 that comprise planar hammer 10, it may bepreferred to use stronger or longer welds 22 that span more length ofthe hammer body sides 20, 21, as is shown.

Additionally, FIGS. 8-11 show planar hammer body 12 including hammerbody holes 68 to allow for a lighter blade. Hammer body holes 68 may beelliptical (including circular), partially elliptical (including ovalshaped and semi-circular), conical, or polygonal in nature, be shaped toform any other known shapes, or shaped using a combination of any of thepreceding shapes.

FIGS. 12-15 show variable hammermill rod hole 62 taking various shapes.In FIGS. 12-13, variable hammermill rod hole 62 is oval shaped, and inFIGS. 14-15, variable hammermill rod hole 62 is partially conical ortear-drop shaped. These shapes still allow for a cylindrical hammermillrod to pass through the hammer 10/11 and will still allow the hammer10/11 to recoil if hammer 10/11 collides with a non-destructible foreignobject in the hammermill. The oval shape in particular will allow thehammer to move in an additional dimension to help ease the impact causedby recoil colliding with non-destructible foreign objects (e.g., inFIGS. 12-13 the hammer is not only be allowed to rotatecircumferentially around the hammermill rod, but is allowed to slide upand down as well). The scope of the present disclosure is not limited tothe use of these shapes for variable hammermill rod hole 62, and othershapes that have similar features and obtain similar results arecontemplated by the present disclosure. Additionally, these shapesproduce extra space that is not occupied by the hammermill rod when thehammermill is in operation. The extra space will prevent the hammers10/11 from locking on the hammermill rod and allow operators of thehammermill to clean the hammermill more easily after repeated grinding.

FIGS. 16-17 show variable hammer saddle 60 using a buckle shape forvariable saddle front and rear surfaces 64, 65 (65 not shown). Thisshape allows the hammer 10/11 to be lighter near the mounting portion ofthe hammer 10/11. If using a shape other than the rectangular shapeshown in FIGS. 8-15 or the buckle shape shown in FIGS. 16-17 forvariable hammer saddle 60, it may be preferred that hammermill saddlestill spans the entire width of hammer body front and rear surfaces 24,25 (25 not shown) so that there is no need for the use of complex welds.Again, it should be noted the present disclosure is not limited to theuse of these shapes for variable hammer saddle 60, and other shapes thathave similar features and obtain similar results are contemplated by thepresent disclosure.

FIGS. 18-19 show an alternative embodiment wherein hammermill rod hole14 is u-shaped to allow easier installation on a hammermill rod withoutdis-assembling said hammermill. In such an embodiment, the variablehammer saddle 60 is one integral piece just as it was in FIGS. 1-4 butincludes some of the material within the bottom of the hammer 10/11 thatthe hammer body 12/13 of FIGS. 1-4 included.

FIGS. 20-23 show non-planar, improved hammers 11 to be installed in ahammermill assembly (not shown). The non-planar hammer 11 of FIGS. 20-23differs from the planar hammer 10 of FIGS. 1-4 because non-planar hammer11 includes a recessed surface 26 and a protruding surface 27 (notshown) opposite recessed surface 26.

The recessed and protruding surfaces 26, 27 recess or protrude viarecessed/protruding edges 29. In the preferred embodiment, recessed andprotruding edges 29 recess or protrude at a depth that is approximatelyidentical to the width of hammer body edges 20, 21. This may causerecessed surface 26 to exist within the same plane as rear surface 25.Additionally, recessed and protruding edges 29 recess or protrude at arate of depth that is approximately forty-five degrees. However, thepresent disclosure is not limited to the configuration described in thepreferred embodiment, as recessed and protruding edges 29 may recess orprotrude any depth or distance and at any rate of depth. Generally,recessed/protruding edges 29 are located below welded contact edges28A-C and above the top of hammermill rod hole 14 towards the center ofnon-planar hammer body 13. The recessed/protruding edges 29 may besymmetrically positioned on hammer 11 such that each are located anequal distance from their respective edges 16, 18.

In the embodiment shown in FIG. 24, a multi-bodied hammermill hammerincluding two non-planar hammers 11 and a planar hammer 10 is arrangedand oriented in a three-pronged fork shaped or trident shapedconfiguration 48. In the trident shaped configuration 48, a planarhammer body 12 and two non-planar hammer bodies 13 are arranged andoriented such that the planar hammer body 12 abuts and is sandwichedbetween the two non-planar hammer bodies 13, and the distal andproximate ends 16, 18 of the hammer bodies 12, 13 extend away from thecenter of the hammer bodies 12, 13 to create three prongs.

In the embodiment shown in FIG. 25, a multi-bodied hammermill hammerincluding two non-planar hammers 11 is arranged and oriented in a bidentshaped or pitchfork shaped configuration 49. In the pitchfork shapedconfiguration 49, two non-planar hammer bodies 13 are arranged andoriented such that the protruding surfaces 27 of the two non-planarhammer bodies 13 abut one another, and the distal and proximate ends 16,18 of the non-planar hammer bodies 13 extend away from the protrudingsurfaces 27 to create two prongs.

FIGS. 26-37 show improved, non-forged hammer assemblies 50, 150, 250,350 to be installed in a hammermill assembly using hammers 10, 11. As isshown in FIGS. 26-28 (and is analogously shown in FIGS. 29-37),proximate ends 18 of hammer bodies 12, 13 are now used to secure hammers10, 11 within hammer mouth 52. Hammer mouth 52 is similar to hammersaddle 30 but is capable of securing more than one hammer 10, 11.

Hammer bodies 12, 13 are welded to hammer mouth 52 where hammer bodyfirst side edges 20 meet hammer mouth first and second teeth shapedsurfaces 54, 55 (second teeth shaped surface 55 not shown; second teethshaped surface 55 is located opposite first teeth shaped surface 54) viawelds 22. Welds 22 are preferably fusion type welds, but the presentdisclosure also contemplates utilizing solid-state welding methods orother types of welding methods known to those skilled in the art. Hammerbodies 12, 13 and hammer mouth 52 may be welded together beforeattachment to a hammermill rod when the hammermill (not shown) isdis-assembled. Again, it should be noted that the present disclosure isalso not limited to the use of welds to secure the hammers 10, 11 to thehammer mouth 52. For example, the hammers 10, 11 could be secured to thehammer mouth 52 via rivets or any other known means for fasteningnon-forged steel together.

Hammer mouth 52 is generally formed by first teeth shaped surface 54having a plurality of fenders or teeth and second teeth shaped surface55 mirroring first teeth shaped surface 54. The teeth shaped surfaces54, 55 are adjoined via puzzle piece shaped surfaces 56, 57 (rear puzzlepiece shaped surface 57 is located opposite front puzzle piece shapedsurface 56 and is not shown).

Hammer bodies 12, 13 interface with root edges 58 to create a continuoussurface for hammermill rod engagement. Teeth 76, 78 are generally thesame width as hammer bodies 12, 13, but may be different widths.

Additional welds may be included, but are not required, where hammerbodies 12, 13 meet other hammer bodies 12, 13. For example, with respectto the embodiment shown in FIGS. 26-37, these welds 22 could be locatednear the center of hammer bodies 12, 13, and could potentially span upto the width of three hammer body side edges 20, 21. These welds couldalso be located at the top and bottom of hammer bodies 12, 13 if thehammer bodies 12, 13 abut one another near where the hammer bodiessecure to hammer mouth 52, as is shown in FIGS. 29-31 and 35-37. In sucha scenario, the hammer mouth 52 will have to be configured such that thedistance between some of the teeth 76, 78 is increased so that at leasttwo hammer bodies may be secured between two teeth. Furthermore, thewelds 22 that would have been associated with these hammer bodies may bereplaced by a single weld 23 of increased width so that the weld canspan the width of both of the hammer body edges 20, 21 between firstteeth 176C, 176D, as is shown in FIGS. 29-31, or between first teeth376B, 376C, 376D, as is shown in FIGS. 35-37. Similarly, another weld 23of increased width may be used on second teeth shaped edge 55 (notshown) between second teeth 178C, 178D, as would be the case in FIGS.29-31, or between first teeth 376B, 376C, 376D, as would be the case inFIGS. 35-37.

FIGS. 26-31 show two configurations of hammer assemblies 50, 150 thatcan secure six total hammers 10, 11 in two separate trident shapedconfigurations 48. FIGS. 32-37 show two configurations of hammerassemblies 250, 350 that can secure six total hammers 10, 11 in threeseparate pitchfork shaped configurations 49.

The present disclosure is not limited to this arrangement of hammerbodies 12, 13 or to the way in which hammer bodies 13 are shown to beoriented. Furthermore, any number and any pattern of hammer bodies 12,13 may be used, including patterns that simply change the orientation ofsome of the hammer bodies 13, but would otherwise be identical. Thepatterns shown in FIGS. 26-37 are for exemplary purposes.

In the embodiment shown FIGS. 26-28, first teeth shaped surface 54 hasseven first teeth 76A-G, which extend away from bottom surface or base70. Similarly, second teeth shaped surface 55 has seven second teeth78A-G positioned opposite first teeth 76A-G. First teeth 76A-G havefirst crown edges 72A-G and second teeth 78A-G have second crown edges74A-G. First and second crown edges 72A-G, 74A-G are interrupted by rootedges 58A-G. Crown edges 72A-G, 74A-G are generally parallel to bottomsurface or base 70. As was stated previously, hammer mouth 52 isconfigured to secure six total hammers 10, 11 in two separate tridentshaped configurations 48.

FIGS. 29-31 show an improved, non-forged hammer assembly 150 to beinstalled in a hammermill assembly using hammers 10, 11. However, theconfiguration of the hammer mouth 152 differs from the configuration ofthe hammer mouth 52 shown in FIGS. 26-28 because hammer mouth 152includes one less tooth on each side and now comprises first and secondteeth 176A-F, 178A-F. As is shown, the middle tooth has been removedsuch that the two central non-planar hammer bodies 13 now abut oneanother at their distal and proximal ends 16, 18. The welds 22 thatwould have been associated with these hammer bodies may be replaced by asingle weld 23 of increased width so that the weld can span the width ofboth of the hammer body edges 20, 21 between first teeth 176C, 176D, asis shown. Similarly, another weld 23 of increased width may be used onsecond teeth shaped edge 155 (not shown) between second teeth 178C,178D.

In the embodiment shown FIGS. 32-34, first teeth shaped surface 254 hasseven first teeth 276A-G, which extend away from bottom surface or base270. Similarly, second teeth shaped surface 255 has seven second teeth278A-G positioned opposite first teeth 276A-G. Every other tooth 276B,276D, 276F, 278B, 278D, 278F in the hammer mouth 252 of FIGS. 32-34 isof increased width. Preferably, although the present disclosure is notlimited to such, every other tooth 276B, 276D, 276F, 278B, 278D, 278Fincreases by the width of the first and second edges 20, 21 of thenon-planar hammer bodies 13. First teeth 276A-G have first crown edges272A-G and second teeth 278A-G have second crown edges 274A-G. First andsecond crown edges 272A-G, 274A-G are interrupted by root edges 258A-G.Crown edges 272A-G, 274A-G are generally parallel to bottom surface orbase 270. As was stated previously, hammer mouth 252 is configured tosecure six total non-planar hammers 11 in two separate pitchfork shapedconfigurations 49.

FIGS. 35-37 show an improved, non-forged hammer assembly 350 to beinstalled in a hammermill assembly using non-planar hammers 11. However,the configuration of the hammer mouth 352 differs from the configurationof the hammer mouth shown in FIGS. 32-34 because hammer mouth 352includes two less teeth on each side and now comprises first and secondteeth 376A-E, 378A-E. As is shown, the smaller middle teeth have beenremoved such that the second and third non-planar hammer bodies 13 andfourth and fifth non-planar hammer bodies 13 now abut one another attheir distal and proximal ends 16, 18. The welds 22 that would have beenassociated with these hammer bodies may be replaced by a single weld 23of increased width so that the weld can span the width of both of thehammer body edges 20, 21 between first teeth 376B, 376C and betweenfirst teeth 376C, 376D, as is shown. Similarly, more welds 23 ofincreased width may be used on second teeth shaped edge 355 (not shown)between second teeth 376B, 376C, and between second teeth 376C, 378D.

Exemplary Processes Employed During the Manufacture Hammermill Hammer(s)

MIG Welding and MIG Tungsten Carbide Embedding in General:

MIG welding is an arc welding process in which a continuous solid wireelectrode is fed through a welding gun and into the weld pool, joiningthe two base materials together. A shielding gas is also sent throughthe welding gun and protects the weld pool from contamination. MIGwelding is a subtype of gas metal arc welding (GMAW).

MIG tungsten carbide embedding is a welding process that depositsextremely hard tungsten carbide particles (70 Rc) in the weld puddle ofa hardfacing wire as it is applied. MIG tungsten carbide incorporatesintact tungsten carbide particles for maximum abrasion resistance, ismore abrasion resistant than chromium carbide, is easy and economical toapply, provides wear life compared to typical hardfacing wires, and maybe used in extreme abrasion environments.

For example, for severe abrasion applications, the PostalloyPS98 ToolSteel Matrix Wire may be used to assist MIG carbide embedding. ThePostalloyPS98 Tool Steel Matrix Wire consists of a vibratory feeder anda standard semi-automatic MIG gun, that delivers metered tungstencarbide particles to a molten weld pool at precisely the right momentprior to the puddle freezing. The result is a weld deposit filled withTungsten Carbide surrounded in a 58 Rc tool steel matrix.

While chromium carbide has served industry adequately for many years,more recent production demands on parts and equipment have dictated aharder, more wear resistant solution. MIG carbide embedding with PS-98offers two to eight times better wear life than typical hardfacingalloys and can be deposited at one-third the cost of tungsten carbidehardfacing wires.

Typical equipment that can benefit from MIG carbiding are mining andconstruction equipment, dredging equipment, mixing, blending, shreddingand processing equipment, drill bit and equipment, agricultural parts.

The present disclosure contemplates MIG tungsten carbide embedding canalso be used to improve the effectiveness of depositing extremely hardtungsten carbide particles onto the hammermill hammer 10/11. Using theprocess of MIG tungsten carbide embedding is especially advantageous forcreating improved hammermill hammers because of the high abrasionenvironments the hammermill hammers are subjected to. Typically,hammermill machines employing hammers of this type are operatedtwenty-four hours a day, seven days a week. This punishing environmentrequires strong and resilient material that will not prematurely orunexpectedly deteriorate.

Safety Precautions:

It should be noted that human welders should observe proper safetyprecautions before using the MIG tungsten carbide embedding processdisclosed herein. Welders should make sure they have the proper safetyapparel and that any potential fire hazards are removed from the weldingarea. Basic welding safety apparel includes but is not limited toleather shoes or boots, cuff-less full-length pants, a flame-resistant,long sleeve jacket, leather gloves, a welding helmet, safety glasses anda bandana or “skull cap” to protect the top of the welder's head fromsparks and spatter.

Equipment:

To perform gas metal arc welding, the basic necessary equipment is awelding gun, a wire feed unit, a welding power supply, a weldingelectrode wire, and a shielding gas supply.

The typical gas metal arc welding gun has a number of key parts—acontrol switch, a contact tip, a power cable, a gas nozzle, an electrodeconduit and liner, and a gas hose. The control switch, or trigger, whenpressed by the welder, initiates the wire feed, electric power, and theshielding gas flow, causing an electric arc to be struck. The contacttip, normally made of copper and sometimes chemically treated to reducespatter, is connected to the welding power source through the powercable and transmits the electrical energy to the electrode whiledirecting it to the weld area. It must be firmly secured and properlysized, since it must allow the electrode to pass while maintainingelectrical contact. On the way to the contact tip, the wire is protectedand guided by the electrode conduit and liner, which help preventbuckling and maintain an uninterrupted wire feed. The gas nozzle directsthe shielding gas evenly into the welding zone. Inconsistent flow maynot adequately protect the weld area. Larger nozzles provide greatershielding gas flow, which is useful for high current welding operationsthat develop a larger molten weld pool. A gas hose from the tanks ofshielding gas supplies the gas to the nozzle. Sometimes, a water hose isalso built into the welding gun, cooling the gun in high heatoperations.

The wire feed unit supplies the electrode to the work, driving itthrough the conduit and on to the contact tip. Most models provide thewire at a constant feed rate, but more advanced machines can vary thefeed rate in response to the arc length and voltage. Some wire feederscan reach feed rates as high as 1200 inches per minute, but feed ratesfor semiautomatic gas metal arc welding typically range from 75-400inches per minute.

Most applications of gas metal arc welding use a constant voltage powersupply. As a result, any change in arc length (which is directly relatedto voltage) results in a large change in heat input and current. Ashorter arc length causes a much greater heat input, which makes thewire electrode melt more quickly and thereby restore the original arclength. This helps operators keep the arc length consistent even whenmanually welding with hand-held welding guns. To achieve a similareffect, sometimes a constant current power source is used in combinationwith an arc voltage-controlled wire feed unit. In this case, a change inarc length makes the wire feed rate adjust to maintain a relativelyconstant arc length. In rare circumstances, a constant current powersource and a constant wire feed rate unit might be coupled, especiallyfor the welding of metals with high thermal conductivities, such asaluminum. This grants the operator additional control over the heatinput into the weld, but requires significant skill to performsuccessfully. The present disclosure contemplates additional powersupplies with varying known functions or advantages may be used inconjunction with or in lieu of the power supply described above to meetthe needs of the individual welder or the specific weld to be performed.

Alternating current is rarely used with gas metal arc welding; instead,direct current is employed and the electrode is generally positivelycharged. Since the anode tends to have a greater heat concentration,this results in faster melting of the feed wire, which increases weldpenetration and welding speed. The polarity can be reversed only whenspecial emissive-coated electrode wires are used, but since these arenot popular, a negatively charged electrode is rarely employed.

Electrode selection is based primarily on the composition of the metalbeing welded, the process variation being used, hammer design and thematerial surface conditions. Electrode selection greatly influences themechanical properties of the weld and is a key factor of weld quality.In general, the finished weld metal should have mechanical propertiessimilar to those of the base material with no defects such asdiscontinuities, entrained contaminants or porosity within the weld. Toachieve these goals a wide variety of electrodes exist. All commerciallyavailable electrodes contain deoxidizing metals such as silicon,manganese, titanium and aluminum in small percentages to help preventoxygen porosity. Some contain denitriding metals such as titanium andzirconium to avoid nitrogen porosity. Depending on the process variationand base material being welded the diameters of the electrodes used ingas metal arc welding typically range from 0.7 to 2.4 millimeters(0.028-0.095 inches) but can be as large as 4 millimeters (0.16 inches).The smallest electrodes, generally up to 1.14 millimeters (0.045 inches)are associated with the short-circuiting metal transfer process, whilethe most common spray-transfer process mode electrodes are usually atleast 0.9 millimeters (0.035 inches).

Shielding gases are necessary for gas metal arc welding to protect thewelding area from atmospheric gases such as nitrogen and oxygen, whichcan cause fusion defects, porosity, and weld metal embrittlement if theycome in contact with the electrode, the arc, or the welding metal. Thisproblem is common to all arc welding processes; for example, in theolder shielded-metal arc welding process, the electrode is coated with asolid flux which evolves a protective cloud of carbon dioxide whenmelted by the arc. In gas metal arc welding, however, the electrode wiredoes not have a flux coating, and a separate shielding gas is employedto protect the weld. This eliminates slag, the hard residue from theflux that builds up after welding and must be chipped off to reveal thecompleted weld.

Metal Preparation:

Unlike stick and flux-cored electrodes, which have higher amounts ofspecial additives, the solid MIG wire does not combat rust, dirt, oil orother contaminants very well. Thus, it may be necessary to use a metalbrush or grinder, clean down to bare metal before striking an arc, andconnect any work clamps to clean metal to reduce the risk of anyelectrical impedance affecting wire feeding performance before startingthe welding process. To ensure strong welds on thicker metal, it may bedesirable to bevel the hammer to ensure the weld fully penetrates to thebase metal.

Equipment Preparation:

Before striking an arc, the welder should check the welder's cables tomake sure all of the cable connections are tight fitting and free offraying or other damage.

Additionally, the welder should select the electrode polarity. MIGwelding requires DC electrode positive, or reverse polarity. Thepolarity connections are usually found on the inside of the machine.

Additionally, the welder should set the gas flow after turning on theshielding gas. The desirable rate of shielding-gas flow dependsprimarily on weld geometry, speed, current, the type of gas, and themetal transfer mode. Welding flat surfaces requires higher flow thanwelding grooved materials, since gas disperses more quickly. Fasterwelding speeds, in general, mean that more gas must be supplied toprovide adequate coverage. Additionally, higher current requires greaterflow, and generally, more helium is required to provide adequatecoverage than if argon is used. Perhaps most importantly, the fourprimary variations of gas metal arc welding have differing shielding gasflow requirements—for the small weld pools of the short circuiting andpulsed spray modes, about 20 to 25 cubic feet per hour is generallysuitable, whereas for globular transfer, around 30 feet per cubic houris preferred. The spray transfer variation normally requires moreshielding-gas flow because of its higher heat input and thus larger weldpool. Typical gas-flow amounts are approximately 40 to 50 cubic feet perhour. If the welder suspects leaks in the gas hose, the welder shouldapply a soapy water solution and look for bubbles. If a leak is spotted,the hose should be discarded and a new hose should be installed.

Additionally, the welder should check tension in the drive rolls and thewire spool hub. Too much or too little tension on either the drive rollsor the wire spool hub can lead to poor wire feeding performance. Thewelder should adjust the tension according to owner's manual.

Additionally, the welder should check consumables, in case they havebeen consumed by previous welds. It may then be desired to remove excessspatter from contact tubes, replace worn contact tips and liners, anddiscard the wire if it appears rusty.

Wire Selection:

For steel, there are two common wire types. It may be preferred to usean AWS classification ER70S-3 for all-purpose welding. It may bepreferred to use an ER70S-6 wire when more deoxidizers are needed forwelding on dirty or rusty steel. As for the wire diameter, it may bepreferred to use a 0.030-inch diameter makes a good all-around choicefor welding the hammer. For welding thinner hammer, a 0.023-inch wiremay be used to reduce heat input. For welding thicker hammers at highertotal heat levels, a 0.035-inch wire may be used.

Stick-out is the length of unmelted electrode extending from the tip ofthe contact tube, and it does not include arc length. The idealstick-out will create a “sizzling” sound during operation. This mayoccur at ⅜ inches, but if the arc sounds irregular, the welder couldadjust the length of the stick-out.

It may also be necessary to select the voltage level and wire feed speedto be used during the welding process. How much voltage and amperage aweld requires depends on numerous variables, including metalthicknesses, type of metal, hammer configuration, welding position,shielding gas and wire diameter speed (among others). Some wire feedsystems have a convenient reference chart located on the inside of thedoor housing. Other wire feed systems are automated and depend on thewire diameter being used and the thickness of hammer to be welded. Thewelder may then selectively fine-tune the welding arc to the welder'spersonal preferences.

Gas Selection:

The choice of a shielding gas depends on several factors, mostimportantly: the type of material being welded, and the processvariation being used. Pure inert gases such as argon and helium are onlyused for nonferrous welding; with steel they do not provide adequateweld penetration (argon) or cause an erratic arc and encourage spatter(with helium). Pure carbon dioxide, on the other hand, allows for deeppenetration welds but encourages oxide formation, which adversely affectthe mechanical properties of the weld. Its low cost makes it anattractive choice, but because of the reactivity of the arc plasma,spatter is unavoidable and welding thin materials is difficult. As aresult, argon and carbon dioxide are frequently mixed in a 75 percentargon/25 percent CO2 blend (also called “75/25” or “C25”) to 90 percentargon/25 percent CO2 blend. C25 may work as the best “all purpose”shielding gas for carbon steel. Generally, in short circuit gas metalarc welding, higher carbon dioxide content increases the weld heat andenergy when all other weld parameters (volts, current, electrode typeand diameter) are held the same. As the carbon dioxide content increasesover 20%, spray transfer gas metal arc welding becomes increasinglyproblematic, especially with smaller electrode diameters.

Argon is also commonly mixed with other gases, oxygen, helium, hydrogenand nitrogen. The addition of up to 5% oxygen (like the higherconcentrations of carbon dioxide mentioned above) can be helpful inwelding stainless steel, however, in most applications carbon dioxide ispreferred. Increased oxygen makes the shielding gas oxidize theelectrode, which can lead to porosity in the deposit if the electrodedoes not contain sufficient deoxidizers. Excessive oxygen, especiallywhen used in application for which it is not prescribed, can lead tobrittleness in the heat affected zone. Argon-helium mixtures areextremely inert, and can be used on nonferrous materials. A heliumconcentration of 50-75% raises the required voltage and increases theheat in the arc, due to helium's higher ionization temperature. Hydrogenis sometimes added to argon in small concentrations (up to about 5%) forwelding nickel and thick stainless-steel workpieces. In higherconcentrations (up to 25% hydrogen), it may be used for weldingconductive materials such as copper. However, it should not be used onsteel, aluminum or magnesium because it can cause porosity and hydrogenembrittlement.

Shielding gas mixtures of three or more gases are also available.Mixtures of argon, carbon dioxide and oxygen are marketed for weldingsteels. Other mixtures add a small amount of helium to argon-oxygencombinations, these mixtures are claimed to allow higher arc voltagesand welding speed. Helium also sometimes serves as the base gas, withsmall amounts of argon and carbon dioxide added. However, because it isless dense than air, helium is less effective at shielding the weld thanargon—which is denser than air. It also can lead to arc stability andpenetration issues, and increased spatter, due to its much moreenergetic arc plasma. Helium is also substantially more expensive thanother shielding gases. Other specialized and often proprietary gasmixtures claim even greater benefits for specific applications.

The Welding Process:

A human welder may utilize the push or forehand technique which involvespushing the gun away from (ahead of) the weld puddle. Pushing usuallyproduces lower penetration and a wider, flatter bead because the arcforce is directed away from the weld puddle. Pushing usually offers abetter view and enables you to better direct wire into the hammer. Awelder may also utilize the drag or backhand technique (also called the,pull or trailing technique) where the welding gun is pointed back at theweld puddle and dragged away from the deposited metal. Draggingtypically produces deeper penetration and a narrower bead with morebuildup.

Travel angle is defined as the angle relative to the gun in aperpendicular position. Normal welding conditions in all positions callfor a travel angle of 5 to 15 degrees. Travel angles beyond 20 to 25degrees can lead to more spatter, less penetration and general arcinstability. Work angle is the gun position relative to the angle of thehammer, and it varies with each welding position and hammerconfiguration. For example, a welder may weld from a flat position, ahorizontal position, a vertical position, an overhead position, etc.With respect to welding carbide onto the hammer, a welder may find it iseasiest to weld from a flat or horizontal position. When welding from ahorizontal position, the welder may have to adjust the gun angle by upto 15 degrees to account for the effects of gravity.

The present disclosure contemplates that the welding process may also besubstantially automated such that a human welder is not necessary formore than providing inputs to an automated system or for supervisorypurposes. Using automated systems to handle the workpieces and thewelding gun can speed up the manufacturing process such that carbide canbe quickly embedded in a plurality of hammermill hammers on an assemblyline.

Location of the Weld:

Carbide, and preferably tungsten carbide, may be welded the periphery ofthe hammermill hammer (also known as contact edges) on the end of thehammer that is located away from where the hammer attaches to thehammermill rod. The weld may be applied any or all of the contact edges.For example, in one embodiment, the weld is applied only to the leadingedge of the hammermill hammer. The weld may cover a portion of the frontand rear surfaces of the hammermill hammer as well. The portion oftungsten carbide to be welded or hardfaced to the front and rearportions of the hammermill hammer may also take any known shape, style,or pattern, such as triangular, rectangular, trapezoidal, semi-circular,“corner-capping,” u-shaped, or any combination thereof.

Carbide may also be welded in a butt weld configuration (180-degreejoint) on both edges of the hammer body where the hammer body and hammersaddle meet. The welds may span the entire with of side u-shaped edgesof the hammer saddle or may be less than the total.

Cold Forming:

Cold forming is the process by which a component is formed using a presstool made up of a punch, die and grip ring. The material is first putthrough an approved heat treatment process, then it is gripped andshaped using a precision-designed punch and die. Approved heattreatments are also used to relieve stress after forming.

Cold forming may also be referred to as work hardening or strainhardening and is a process for strengthening a metal or polymer byplastic deformation. This strengthening occurs because of dislocationmovements and dislocation generation within the crystal structure of thematerial. Many non-brittle metals with a reasonably high melting pointas well as several polymers can be strengthened in this fashion. Certainalloys are more prone to this than others. Alloys not amenable to heattreatment, including low-carbon steel, pure copper, and aluminum, areoften work-hardened. Some materials cannot be work-hardened at lowtemperatures, such as indium.

The cold forming process is characterized by shaping the workpiece at atemperature below its recrystallization temperature, usually at ambienttemperature. Cold forming techniques are usually classified into fourmajor groups: squeezing, bending, drawing, and shearing. Applicationsinclude the heading of bolts and cap screws and the finishing of coldrolled steel. In cold forming, metal is formed at high speed and highpressure using tool steel or carbide dies. The cold working of the metalincreases the hardness, yield strength, and tensile strength.

Cold forming provides a number of advantages over other forming methodsincluding hot forming, superplastic forming etc. For example, coldforming is much faster than hot forming or superplastic forming, andhence is appropriate for higher volume production. Relatively complexshapes can be formed by careful tool design. High surface profiletolerances due to uninterrupted grain orientation in work formed metals,giving increased tensile strength. Finally, cold forming typically costsless than hot forming, superplastic forming, and machining from a solid.

It is to be appreciated cold forming may be used in particular duringthe manufacturing process to shape the improved hammers 10, 11 of thepresent disclosure. For example, the recessed and protruding surfaces26, 27 may be formed by providing a piece of sheet metal, putting thesheet metal through an approved heat treatment process, and gripping andshaping the hammer using a precision-designed punch and die.

Hot Forming:

In hot forming processes, metals are plastically deformed above theirrecrystallization temperature. Being above the recrystallizationtemperature allows the material to recrystallize during deformation.This is important because recrystallization keeps the materials fromstrain hardening, which ultimately keeps the yield strength and hardnesslow and ductility high. Hot forming processes include rolling, forging,extrusion, and drawing.

The lower limit of the hot working temperature is determined by itsrecrystallization temperature. As a guideline, the lower limit of thehot working temperature of a material is 60% its melting temperature (onan absolute temperature scale). The upper limit for hot working isdetermined by various factors, such as: excessive oxidation, graingrowth, or an undesirable phase transformation. In practice materialsare usually heated to the upper limit first to keep forming forces aslow as possible and to maximize the amount of time available to hot workthe workpiece.

The most important aspect of any hot working process is controlling thetemperature of the workpiece. 90% of the energy imparted into theworkpiece is converted into heat. Therefore, if the deformation processis quick enough the temperature of the workpiece should rise, however,this does not usually happen in practice. Most of the heat is lostthrough the surface of the workpiece into the cooler tooling. Thiscauses temperature gradients in the workpiece, usually due tonon-uniform cross-sections where the thinner sections are cooler thanthe thicker sections. Ultimately, this can lead to cracking in thecooler, less ductile surfaces. One way to minimize the problem is toheat the tooling. The hotter the tooling the less heat lost to it, butas the tooling temperature rises, the tool life decreases. Therefore,the tooling temperature must be compromised.

Advantages of using hot forming processes include a decrease in yieldstrength, (therefore it is easier to work and uses less energy orforce), an increase in ductility, elevated temperatures increasediffusion which can remove or reduce chemical inhomogeneities, pores mayreduce in size or close completely during deformation, and in steel, theweak, ductile, face-centered-cubic austenite microstructure is deformedinstead of the strong body-centered-cubic ferrite microstructure foundat lower temperatures.

Usually the initial workpiece that is hot worked was originally cast.The microstructure of cast items does not optimize the engineeringproperties, from a microstructure standpoint. Hot working improves theengineering properties of the workpiece because it replaces themicrostructure with one that has fine spherical shaped grains. Thesegrains increase the strength, ductility, and toughness of the material.

The engineering properties can also be improved by reorienting theinclusions (impurities). In the cast state the inclusions are randomlyoriented, which, when intersecting the surface, can be a propagationpoint for cracks. When the material is hot worked the inclusions tend toflow with the contour of the surface, creating stringers. As a whole thestrings create a flow structure, where the properties are anisotropic(different based on direction). With the stringers oriented parallel tothe surface it strengthens the workpiece, especially with respect tofracturing. The stringers act as “crack-arrestors” because the crackwill want to propagate through the stringer and not along it.

In a preferred embodiment, the hammers 10, 11 of the present disclosurecomprise high-carbon steel and a hot-forming process is used to shapeany portions of the improved hammers 10, 11 that may be difficult toform through a cold working process or some other type of manufacturingprocess. Furthermore, it is to be appreciated hot-forming process may beused to shape any of the surfaces of the hammers, and that the surfaces(or at least portions of the surfaces) of the hammers may take any knowntwo-dimensional shape, such as ovals (including ellipses, circles,etc.), partial ellipses (including semicircles), stadiums, regularpolygons (including triangles, rectangles, etc.), irregular polygons,cones, shapes of letters or numbers, curves extruded in two dimensions,or a combination of any of the preceding two-dimensional shapes. Forexample, FIGS. 38-49 show alternative hot formed hammer bodies 12′, 13′which include a U-shaped proximate end 18′ formed as a result of a hotworking process. The U-shaped proximate end 18′ is provided in lieu ofthe proximate end 18 disclosed above. In particular, the U-shapedproximate end 18′ helps appropriately space adjacent hammers 10, 11 whenthe hammers 10,11 are assembled onto a hammermill rod.

FINAL MATTERS

The foregoing description has been presented for purposes ofillustration and description and is not intended to be exhaustive or tolimit the invention to the precise form disclosed. The descriptions wereselected to explain the principles of the invention and their practicalapplication to enable others skilled in the art to utilize the inventionin various embodiments and various modifications as are suited to theparticular use contemplated. Although particular constructions of thepresent invention have been shown and described, other alternativeconstructions will be apparent to those skilled in the art and arewithin the intended scope of the present invention.

What is claimed is:
 1. A method of manufacturing a hammermill hammer comprising: heating sheet metal an elevated temperature; bringing the sheet metal into contact with a hot die while a hot punch descends into the die; holding the sheet metal under forming pressure for a period of time; and shaping the sheet metal to form a hammer with a substantially U-shaped first end; wherein a second end of the hammer is for contact and delivery of momentum to material to be comminuted.
 2. The method of claim 1 wherein the sheet metal comprises high-carbon steel.
 3. The method of claim 1 further comprising removing material from the first end of the hammer to form a rod hole.
 4. The method of claim 3 further comprising assembling the hammer onto a hammermill rod of a hammermill assembly.
 5. The method of claim 1 wherein shaping the sheet metal comprises rolling, forging, extruding, or drawing the sheet metal to form the hammer.
 6. A method of manufacturing a hammermill hammer comprising: providing sheet metal; putting the sheet metal through a heat treatment process; and gripping and shaping a hammer from the sheet metal using a precision-designed punch and die.
 7. The method of claim 6 wherein the sheet metal comprises low-carbon steel or aluminum.
 8. The method of claim 6, wherein, after gripping and shaping the hammer using a precision-deigned punch and die, the formed hammer comprises: a front surface; a rear surface opposite the front surface; a recessed surface; a protruding surface located opposite the recessed surface; a first end; a second end for contact and delivery of momentum to material to be comminuted; and a rod hole for securing the hammer to a hammermill rod of the rotatable hammermill assembly.
 9. A method for manufacturing a hammermill hammer comprising: providing a welding gun including a control switch, a contact tip, and a gas hose; providing a wire feed unit, a welding power supply, a welding electrode wire, and a shielding gas supply; setting a flow rate of shielding gas flow to be supplied by the shielding gas supply; striking an arc by pressing the control switch of the welding gun to initiate the wire feed unit, the welding power supply, and the shielding gas flow; and hardfacing the carbide onto the hammermill hammer.
 10. The method of claim 9 wherein tungsten carbide is welded to the periphery of the hammermill hammer at an end of the hammermill hammer that is located away from where the hammer attaches to a hammermill rod.
 11. The method of claim 9 further comprising removing rust and other surface contaminants from the hammer prior to welding.
 12. The method of claim 9 further comprising beveling the hammer to ensure the weld fully penetrates to the base metal.
 13. The method of claim 9 further comprising checking whether the cable connectors are tight fitting and free of fraying or other damage.
 14. The method of claim 9 further comprising selecting reverse polarity.
 15. The method of claim 9 further comprising chemically treating the contact tip to reduce spatter and wherein the contact tip of the welding gun is made of copper.
 16. The method of claim 9 further comprising selecting a voltage level and a wire feed speed to be used during the welding step.
 17. The method of claim 9 wherein the welding gun comprises a gas nozzle to direct the shielding gas evenly during the hardfacing step.
 18. The method of claim 9 further comprising: removing excess spatter from the contact tubes; and replacing the contact tip, electrode conduits and liners, and the gas hose and the welding electrode wire.
 19. The method of claim 9 wherein the process is automated.
 20. The method of manufacturing a hammermill hammer comprising: hot working sheet metal to form at least a portion of the hammermill hammer; cold working the sheet metal to form at least another portion of the hammermill hammer; and MIG welding carbide onto the hammermill hammer. 